A 5-year-old boy presented with redness and watering in his left eye for 3 days. The child was on treatment for pre B-cell acute lymphoblastic leukaemia (ALL). At the time of diagnosis of ALL, he had presented to the hospital with fever for 2 weeks’ duration and found to have hepatosplenomegaly with thrombocytopenia. Bone marrow studies and Cerebrospinal fluid (CSF) analysis confirmed the diagnosis of ALL with central nervous system (CNS) involvement and he received two consecutive weekly intrathecal methotrexate doses. He was started on treatment as per regimen A (three drug induction) of UKALL 2003 protocol.1 At the end of induction, bone marrow analysis was consistent with disease remission with minimal residual disease <0.01% suggestive of standard risk. At the time of presentation to us, the child had just completed delayed intensification phase and started on first maintenance cycle of treatment. On ophthalmologic evaluation, the best-corrected visual acuity was 20/20 in the right eye and 20/200 in the left eye. Anterior segment examination revealed circum-corneal congestion in the left eye, anterior chamber cells 4+ with white hypopyon measuring around 2 mm in height (figure 1).2 The pupil was meiotic, pupillary reaction was sluggish. Lenticular opacity was present in the posterior subcapsular region. Intraocular pressure was raised to 28 mm Hg. Ultrasound B-scan showed choroidal thickening and exudative retinal detachment. CSF analysis and bone marrow aspiration were negative for leukaemic cells. Anterior chamber paracentesis revealed atypical lymphoid cells suggestive of leukaemic infiltration (figure 2). Anterior uveitis with hypopyon in the left eye was the sole clinical feature suggestive of relapse of ALL in this child. Reinduction treatment as per ALL R3 protocol was started following which, ocular and cranial radiotherapy, as well as subsequent bone marrow transplant, was planned. Unfortunately, he succumbed to his illness during the reinduction phase within a couple of months after relapse was diagnosed.